JPS63241486A - Method and device for defining nuclear dosage - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to the detection of nuclear radiation and the determination of nuclear radiation!8 radiation fi3.

[Conventional technology and problems]

So-called thermoluminescent substances are well known. In particular, the self-supporting thermoluminescent material Y; 1 is fluorinated Na-Rum. Industrial diamond is also known to have the properties of a thermoluminescent material, as described in South African Patent Application No. 86/19f38. Another well-known thermoluminescent material is rectangular boron nitride (CBN). can give.

When a crystalline thermoluminescent substance is subjected to nuclear radiation, e.g. radiation of X-rays, alpha particles, neutrons, protons, gamma rays or electrons, at appropriate low temperatures, free electrons or holes become trapped in lattice defects in the crystal, or If the temperature is low enough it can remain trapped for quite a long time.

However, as the temperature increases +f#, the electrons or holes return to a stable energy level, often accompanied by the emission of light.

This phenomenon is used in medical technology to determine nuclear parabolic stars. For example, a thermoluminescent crystal, which generates the above-mentioned fluctuations in the energy level during exposure to nuclear radiation such as X-rays, is attached to a person receiving nuclear radiation such as X-rays. This crystal is then removed from the 4+ body, and the crystal and thus the radiation that the wearer was exposed to during the bath (Test 1 to determine the measurement 017 of 4).
]. The 6-way test technique involves placing the irradiated crystal on a support surface that is heated from below using a resistance heater. The light emitted by the crystal when heated is collected by a photomultiplier tube (PM tube).

The rays collected by this PM tube are then used to establish the initial nuclear radiation F- from the known relationship between the collected rays and the radiation tH.

Although the principle of this technique is correct, there are great difficulties in determining the reproducibility of the results. The main reason for this discrepancy in results is the requirement that the crystal be positioned very accurately and uniformly on its support. Variable results due to different heat intensities applied to uneven beam collection by the crystal and one M tube, since the crystal is not positioned exactly the same each time. is obtained. Furthermore, the crystal can only be heated from one side, which promotes non-uniformity during heating. Moreover, the main part of the light rays emitted by the crystal body is scattered and all of the heat is not collected by the PM tube.

Another problem is that the intensity of the emitted light is low, especially in the case of thermoluminescent diamonds, which also requires very precise positioning of the diamond in the PM tube. In addition, it can take as long as 20 to 30 seconds to heat a diamond to a specified temperature using a resistance heater that is used in a convex manner.

It is believed that thermoluminescent media can be used effectively in medical technology for the identification of radiation sources (h). The main reason for this is that carbon, diamond, has a composition that closely resembles that of the human body.

That is, the radiation absorbed by the die X/'End is close to the radiation absorbed by the human body, and thus diamond provides a reliable indication of the radiation range to which the human body is exposed.

[Object and structure of the invention]

The present invention aims to provide a method and apparatus for determining nuclear radiation td using thermoluminescent crystals.

One feature of the invention is to provide a method for establishing nuclear radiation between a thermoluminescent crystal upon which a thermoluminescent crystal is irradiated, and heating the crystal to a temperature suitable for photoluminescence to take place. The method includes the steps of collecting the rays emitted by the crystal, and rxing the radiation ω from the crystal, and supporting the crystal against the force of Φ during heating using an ascending gas flow. A method is provided.

According to another feature of the invention, the thermoluminescent crystal is subjected to irradiation by means of an apparatus for determining the nuclear radiation FIla+ (Kf) suitable for the luminescence to take place. It has a device for heating the crystal to a certain Ufflj, a device for collecting the light rays emitted by the crystal, and a device for measuring the radiation dose from the crystal. An apparatus for determining the nuclear radiation dose is provided, including an apparatus for creating an ascending gas flow to support it against gravity.

The crystal body is supported and heated by a high t gas flow.

However, the crystal is initially supported by a low-temperature gas flow and its (
9. It may be replaced by a hot gas flow.

Preferably, an integrating sphere is used to collect the 111-order rays of the crystal, and the crystal is supported and heated within the integrating sphere. For example, a vertical light transmission tube is provided through the integrating sphere member.

The crystal is dropped into the tube while a gas flow is applied over the tube.

The invention may also be used to determine between radiation from distant radiation sources. Apart from this, it may also be used to periodically establish a radiation FAFA from a single source. In this case, the crystal body is irradiated υ
Each cycle, the tube is dropped to the bottom end of the tube, and then placed on the gas flow into the integrating sphere. Confirm the release Q4 line fi1.

In one embodiment of the invention, the crystal is confined alone or with other similar crystals within a light transmission body, typically made of glass.

〔Example〕

In the drawings, the integrating sphere is indicated by reference numeral 10. The inner surface of the sphere is coated with a barium tetrachloride photometric paint having a neutral spectral anti-Ω·j coefficient. It extends diametrically from the opening 15 at the bottom.

A tube 16 extends from the bottom of tube 12. Branch pipes 18 and 20 are connected to this pipe 16 via a three-way valve 22. A light-tight baffle 24 is provided at the two ends or openings 14 of the tube 12, which prohibits light from entering or exiting the tube or the integrated sphere, but allows air to pass through. A function for lifting the baffle and dropping the crystal into the pipe 12 is installed.

1) M tubes 28 are arranged around the outer periphery of the integrated sphere, the signals from these tubes are sent to the process device 32 via the cable 30, and the process IJi it'7 visually displays the indicator 34. . 11 The M tube 28 is selected to be able to respond to rays of various waves 1).

A hatch 36 (411) is provided at the bottom end of tube 12 to allow extraction of the crystals once they have been tested. Branch tube 20 is connected to a source of compressed cold air, and branch tube 18 is connected to a source of compressed hot air. connected to the source.

In using this device, the valve 22 is operated to create a top tear, cold air flow within the tube 12. A thermoluminescent crystal 25, which is a suitable diamond crystal or rectangular boron nitride crystal, is placed in advance to avoid irradiation with nuclear radiation and dropped into the tube, and a baffle device is used to allow light to enter and exit the integrated sphere. The updraft is returned to a position that prevents this from occurring and still allows the cold air flow to flow out of the tube.The updraft is an equilibrium in which the crystal is supported by the cold air flow against gravity at the center of the accumulated sphere in the tube. Once the crystal reaches this state, valve 22 is operated to stop the cold air flow and replace it with a similar i!
a) Apply a hot air flow to maintain the suspended position of the crystal at the center of the collecting sphere.

The hot air merely supports the crystal and heats it rapidly. Typically, the crystal is in the form of a cube, and the effect of the air flow is to cause the crystal to turn and change its orientation while still remaining centered in the sphere. Since the hot air current hits the entire surface of the crystal in this manner, the crystal is heated uniformly. The crystal body is generally heated to a humidity of less than 500'C.

When this crystal is heated, light is emitted. This light is collected by the PM tube around the collecting sphere, and appropriate signals indicative of the collection light beam are sent to the processing device 32 where the collected light beam signals are integrated and analyzed.

By the processing device that integrates the collected light signal, the radiation value J is determined by the relationship between the collected light beam and the radiation'
lo and this number is visually displayed on the display device iff 34.

In addition to having the function of uniform heating of the thermoluminescent crystal, this device also has the advantage that the emitted light, which was initially collected in one of the PM tubes, is discarded on the inner surface of the collecting sphere, and then finally This has the advantage that all of the emitted Q and J light is collected by the PM tube. Therefore, it is believed that the present device produces a possible result with the positive lif' and the iteration y1.

Once a particular crystal has been tested in the manner described above, the high moisture flow is stopped and the crystal is gently dropped into the hatch 36 through which it is removed in preparation for the next crystal.

This device can be used by radiation wave therapists and patients receiving radiation therapy. S
It is believed that this method is highly suitable for medical technology, where it is desirable to detect radiation exposure of the human body during bathing. It is proposed to fix a thermoluminescent diamond crystal to the human body during exposure to radiation, and then to display this diamond in the manner described above.

As already mentioned, Difmond has the same composition as the human body, so it is particularly suitable for the above-mentioned applications.

Another advantage of using diamond is that the intensity of the emitted light increases towards the red end of the spectrum.

Therefore, the PM tube can be selected to exhibit responsivity at the red end of the spectrum. This eliminates the need to use 41 different types of PM tubes to respond to various wavelengths.

(In the case of an embodiment that can be modified in any way, a rectangular nitride crystal is housed in a light-transmitting body such as a glass bulb, and the tube is piped in the manner described above.) Drop within 12.

Kiyoshi F/ is also suitable for determining the amount of radiation received by a crystal body at a far-reaching point when it receives a bath q·1. Also, radiation from a single source $! It is possible to slightly modify the device to obtain periodic coagulation continuity readings of Jffi. In this case, a crystal body or a body through which the light confined crystal body is kept stationary at the lower end of the tube 12 irradiated by the radiation source. This can be accomplished by constructing the crystal or body so that it can be placed on a perforated support (not shown) extending across the lower end of the tube 12 above the hatch 36.

When it is desired to take a reading, a stream of cold air is created to bring the crystal or body into equilibrium at the center of the collecting sphere. Then, a hot air stream is introduced as described above and the emitted light is collected. Once the reading has been taken, the control valve 22 is operated to reduce or stop the airflow and allow the crystal or body to fall back under the action of gravity to the lower end of the tube 12. Once cooled, the crystal or body can be exposed to radiation from the same source again before taking the next reading. A cold IJ1 device (not shown) is installed to cool the crystal or body each time the process is repeated.
I! J' can be done. Due to this i position, the fixed radiation source h
This makes it possible to repeatedly monitor the radiation of sr et al.

Also, instead of using a cold air flow followed by a hot air flow, a hot air flow is used.
) can be used to support the crystal in the center of the collecting sphere and heat it. In this case, the associated piping system has multiple M
No special valve equipment is required.

In the illustrated example, a total of six PM tubes are used, but it should be noted that fewer or one PM tube can also be used. When a suitable filter is installed on the PM tube, the signal j! Not only will it be 1, but it will also be 1 for light with a wavelength of 0, so (
For the purpose of σ1 research, it is desirable to throw a large number of heads.

Regardless of the number of PM tubes used in this device, it is necessary to accurately adjust the tubes by 11 steps at the start of the AST. This is done by introducing a beam of known intensity into the integrating sphere using an optical fiber and then calibrating the PM tube to give the appropriate reading for the known intensity.

EXAMPLE 4 In a practical example using the same apparatus as shown, a 3M thermoluminescent diamond was subjected to radiation for one minute. During this irradiation, the crystal body emitted light, and this light disappeared approximately 1 minute after the irradiation stopped. An overhead thermal air flow was created within the apparatus and adjusted to a level suitable for supporting the crystal in the center of the collecting sphere. A diamond was dropped into a tube flowing with hot air and allowed to reach an equilibrium position where it was supported against gravity at the center of the sphere.

A single PM tube was placed to collect the reflected light around the inner surface of the collecting sphere. When the diamond crystal is stabilized, the PM tube is activated and the output signal of A is sent to the D converter, and the digital signal is sent to the converter to the process equipment where it is output. The Sl test of the radiation Q-1 line m was performed. Second
The figure shows a graph of the amplitude (in arbitrary units) of the PM tube signal versus time, with the area under the curve representing the collected rays. The radiation td was calculated from the above values according to the known relationship between the radiation beam and the collected beam.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an apparatus for detecting and determining nuclear radiation QJ rays using an integrated sphere according to the present invention, and FIG.
FIG. 1 is a graph showing the relationship between the amplitude of a tube signal and time. 10... Integrated sphere, 12... Light transmission tube, 14.15... Frontage, 18.20...
・Branch pipe, 22... Three-way valve, 24...
... Baffle device that does not transmit light, 25 ... Crystal body, 28 ... PM tube, 32 ... Process device, 34 ... Visual indicator, 36...
Hatsuchi.

Claims (21)

[Claims] (1) A method of determining the nuclear radiation dose to which a thermoluminescent crystal has been exposed involves heating the crystal to a temperature suitable for its cold luminescence and collecting the light emitted by the crystal. A method for determining a nuclear radiation dose, comprising the step of calculating the radiation dose from this, and using an upper field gas flow to support the crystal against gravity while heating the crystal. 2. A method according to claim 1, characterized by the step of: (2) supporting the crystal on an upward flow of hot gas that heats the crystal. 3. A method according to claim 2, characterized by the step of: (3) supporting the crystal within a collecting sphere used to collect the light rays emitted by the crystal. 4. A method according to claim 3, characterized by the steps of: (4) initially supporting the crystal within the collecting sphere by an upward flow of cold gas, and then replacing the cold gas flow with a hot gas flow. (5) Dropping the crystal into the upper end of a beam transmission tube that extends vertically through the integrated sphere, directing the gas flow into the lower end of the tube and lifting the crystal into the destination tube to support the crystal at or near the center of the integrated sphere. A method according to claim 3 or 4, characterized by the step of: (6) After collecting the radiation, the method further comprises the step of: reducing or terminating the gas flow within the tube so that the crystals fall into the lower end of the tube.
Method by term. (7) further comprising the step of holding the crystal at the lower end of the tube in a position to re-irradiate the crystal with nuclear radiation, reforming the former gas flow and raising the crystal into the tube to further determine the radiation dose; A method according to claim 6, characterized in that: 8. A method according to claim 7, characterized in that the steps of the method are repeated periodically for the periodic determination of the radiation dose from a single source. (9) A method according to any one of claims 1 to 8, characterized in that the gas flow is an air flow. (10) According to any one of claims 1 to 9, characterized in that the crystal is confined in the main body of the light beam transmitting material alone or together with other similar crystals. Method. (11) A method according to any one of claims 1 to 10, characterized in that the crystal is diamond or rectangular boron nitride crystal. (12) A device for determining the amount of nuclear radiation to which a thermoluminescent crystal has been exposed, including a device for heating the crystal to a temperature suitable for cold luminescence; a device for collecting the rays of light and a device for calculating the radiation dose therefrom, and also a device for creating an ascending gas flow to support the crystal against gravity during heating. Nuclear radiation dose determination device including 13. An apparatus according to claim 12, characterized by a device for forming an upper bound hot gas flow which supports the crystal body against gravity and also heats the crystal body to a suitable temperature. (14) Claim 13 characterized by an apparatus operative to first form an ascending cold gas stream for supporting the crystal body against gravity and then to convert this cold gas stream into a hot gas stream. Device according to section. 15. Device according to claim 13 or 14, characterized in that the device for collecting the emitted light beam is an integrated sphere in which a crystal body is supported. (16) having a beam transmission tube extending vertically through the integrated sphere, the tube having an opening at the upper end through which the crystal can fall, and a source of compressed hot gas connectable to the lower end of the tube; Device according to claim 15, characterized in that it comprises: (17) Claim 1 characterized by a source of compressed cold gas connectable to the lower end of the tube and a valve device operable to selectively connect the source of cold gas or the source of hot gas to the tube.
Apparatus according to clause 6. 18. Device according to claim 16 or 17, characterized in that a closure is provided for the upper end of the tube, said closure being opaque to light but permeable to gas flow. (19) A device according to any one of claims 1 to 18, characterized in that the crystal body is confined in the light transmission body, alone or together with other similar crystal bodies. (20) The device according to claim 19, wherein the crystal is a diamond or rectangular boron nitride crystal. (21) The device according to claim 19 or 20, characterized in that the light transmission body is made of glass.